• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.187-195
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• 2011

In this study, dilute acid pretreatment of $Liriodendron$ $tulipifera$ was performed for enzymatic hydrolysis. As the pretreatment temperature was increased, enzymatic hydrolysis and enzyme adsorption yield also increased. The highest enzymatic hydrolysis yield was 57% (g/g) and enzyme adsorption was 44% (g/g). Enzymatic hydrolysis yield was determined with weight loss of pretreated biomass by enzyme, and enzyme adsorption was a percentage of enzyme weight attaching on pretreated biomass compared with input enzyme weight. When $L.$ $tulipifera$ was pretreated with 1% sulfuric acid at $160^{\circ}C$ for 5 min., hemicellulose was significantly removed in pretreatment, but the lignin contents were constant. Other changes in surface morphology were detected on biomass pretreated at $160^{\circ}C$ by a field emission scanning electron microscope (FESEM). A large number of spherical shapes known as lignin droplets were observed over the entire biomass surface after pretreatment. Hemicellulose removal and morphological changes improved enzyme accessibility to cellulose by increasing cellulose exposure to enzyme. It is thus evidence that enzyme adsorption is a significant factor to understand pretreatment effectiveness.

• KSBB Journal
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• 제13권5호
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• pp.621-625
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• 1998

The raw starch hydrolysis by amylase prepared from alkaline-tolerant Bacillus sp. were investigated. Degree of hydrolysis(%) of 5%(w/v) raw rice, corn and potato starch by this enzyme were about 40, 25 and 20%, respectively. The hydrolysis action on raw starch by change of blue value was similar to the action pattern of exo ${\beta}$-amylase. The hydrolysis products of rice starch were mainly glucose and maltose. Oligosaccarides were also detected. From the above results, this enzyme was considered as exo type ${\alpha}$-amylase. This enzyme activity on the raw starch and the gelatinized starch were 28.40 and 86.60 IU/mg protein, respectively, and the ratio of raw starch-digesting activity to gelatinized starch-digesting activity (raw starch digestivity) was about 32%. The Km values for the raw and the gelatinized starch were 4.22 and 3.0mg/mL, respectively, and the VmaX values were 0.20 and 0.31mg/mL/min, respectively.

• 대한한의학회지
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• 제27권2호
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• pp.103-110
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• 2006

Objectives : This study was conducted to investigate the effects of ginseng saponins and commercial surfactants such as Triton X-100, sodium deoxycholate, and sodium dodecyl sulfate on the gastric enzyme-catalyzed hydrolysis. Methods : Saponins (a surface-active plant component) from fresh ginseng root were extracted to examine its effect on the gastric enzyme-catalyzed hydrolysis. Commercial surfactants such as Triton X-100, sodium deoxycholate, and sodium dodecyl sulfate were also employed in the hydrolysis system to compare their effects with that of the ginseng saponins. The effects of surfactants on the gastric enzyme-catalyzed hydrolysis were measured by using a spectrophotometer. A spectropolarimeter was used to examine the conformational change of enzymes and substrates by the addition of ginseng saponins into the system. Results : Both the tryptic and the peptic digestion of milk casein or eggalbumin were slightly improved with an increase in the amount of ginseng saponins in the system. Triton X-100 showed an effect similar to that of ginseng saponins, while sodium dodecyl sulfate and sodium deoxycholate diminished the hydrolysis. Circular dichroism spectra of enzymes and substrates was significantly changed by the addition of ginseng saponins into the system. Conclusions : These results show that ginseng saponins affect positively the gastric enzyme-catalyzed hydrolysis, and suggest that the digestion of substrates by gastric enzymes is affected by the change of enzyme conformation by ginseng saponins.

• 대한약침학회지
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• 제17권1호
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• pp.44-50
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• 2014

Objectives: This study was undertaken to isolate a fibrinolytic enzyme from the snake venom of Gloydius blomhoffii siniticus and to investigate its enzymatic characteristics and hemorrhagic activity as a potential pharmacopuncture agent. Methods: The fibrinolytic enzyme was isolated by using chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fibrin plate assay. The characteristics of the enzyme were investigated using fibrin plate assay, protein hydrolysis analysis, and hemorrhage assay. Its amino acid composition was determined. Results: The fibrinolytic enzyme with the molecular weight of 32kDa (FE-32kDa) from Gloydius blomhoffii siniticus showed a fibrin hydrolysis zone at the concentration of 0.2 mg/mL in the fibrin plate assay. The fibrin hydrolysis activity of the enzyme was inhibited completely by ethylenediaminetetraacetic acid (EDTA), ethyleneglycoltetraacetic acid (EGTA), and 1, 10-phenanthroline, thiothreitol and cysteine, and partially by phenylmethanesulfonylfluoride (PMSF). Metal ions such as $Fe^{2+}$ and $Hg^{2+}$ inhibited the fibrin hydrolysis completely, but $Zn^{2+}$ enhanced it. FE-32kDa hydrolyzed ${\alpha}$-chain but did not hydrolyze ${\beta}$-chain and ${\gamma}$-chain of fibrinogen. High-molecular-weight polypeptides of gelatin were hydrolyzed partially into low-molecular-weight polypeptides, but the extent of hydrolysis was limited. FE-32kDa induced hemorrhage beneath back skin of mice at the dose of $2{\mu}g$. Conclusions: FE-32kDa is a ${\alpha}$-fibrin(ogen)olytic metalloprotease that requires $Zn^{2+}$ for fibrinolytic activity and causes hemorrhage, suggesting that the enzyme is not appropriate for use as a clinical pharmacopuncture.

• Journal of the Korean Wood Science and Technology
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• 제17권3호
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• pp.45-51
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• 1989

A major problem in the enzymatic hydrolysis of lignocellulosic substrates is the very strong bonding of cellulase to lignin and even cellulose in the hydrolysis residues. This phenomenon inhibits recycle of the cellulase which is a major expense of the enzymatic hydrolysis process. In this paper, autohydrolyzed wood was delignified by two-stage with a 0.3% Na OH extraction and oxygen-alkali bleaching and was subjected to enzymatic hydrolysis with cellulase. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method. the first recycling showed relatively high hydrolysis rate of 97.4%. Even at the third recycle. hydrolysis rate was 86.7 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted very high hydrolysis rate(97.0-97.7%). Even the third recycling showed about 94.2%. Authoydrolysis of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a substrate for enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.166-172
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• 1997

Aspergillus niger was selected as a strain producing the potent raw starch hydorlyzing enzyme. These experiments were conducted to investigate the conditions of the glucoa- mylase production, the purification of the enzyme, some characteristics of the purified enzyme and hydrolysis rate on various raw starches such as com, rice, potato, glutinous rice, sweet potato, wheat and barley. The optimum cultural temperature and time for the enzyme production on wheat bran medium were $30^{\circ}C$ and 96hrs, respectively. The respective addition of yeast extract and nutrient broth on wheat bran medium increased slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 30.7u/mg-protein and the yield of enzyme activity was 25.8%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 56,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH3.7. The optimum temperature and pH were $65^{\circ}C$ and pH 4.0, respectively. The purified enzyme was stable in the pH range of pH 3.0-9.5 and below $45^{\circ}C$, and its thermal stability was slightly increased by the addition of $Ca^{2+}$. The purified enzyme was activated by $Co^{2+},\;Sr^{2+},\;Mn^{2+},\;Fe^{2+},\;Cu^{2+}$. Raw rice starch, raw corn starch, raw glutinous rice starch, raw sweet potato starch, raw wheat starch and raw barley starch showed more than 90% hydrolysis rate in 48hrs incubation. Even raw potato starch, most difficult to be hydrolyzed, showed 80% hydrolysis rate. The purified enzyme was identified as glucoamylase.

• 한국식품저장유통학회지
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• 제14권4호
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• pp.394-399
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• 2007

본 연구에서는 전두유의 가수분해 조건에 따른 품질 특성을 조사하였다. 그 결과 효소제(KMF-G) 농도가 증가함에 따라 전두유 가수분해물의 당도, 칼슘 내인성, 및 총 유리아미노산 함량은 증가하였으며, SDS-PAGE 분석 결과 단백질의 분자량 변화는 0.20%(w/w)와 0.35%(w/w) 농도에서 유사한 패턴을 나타냈다. 전두유 가수분해물은 효소제(KMF-G) 농도 0.20%(w/w), 가수분해 시간 60분에서 가장 우수하게 나타났다. 전두유 가수분해물을 115, 130 및 $145^{\circ}C$에서 15초간 살균하였을 때 품질변화는 크지 않았다. 이상의 결과 전두유의 가수분해 최적조건은 효소제(KMF-G) 농도 0.20%(w/w), 가수분해 시간 60분으로 설정할 수 있었으며 식품소재로의 다양한 활용이 기대된다.

• 한국미생물·생명공학회지
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• 제19권4호
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• pp.377-382
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• 1991

우지를 lipase에 의해 지방산과 글리세린으로 분해하는 반응을 액상 및 고상에서 수행하였다. 올리브유를 기질고 lipase OF 360(일본 메이토사 제품)의 특성을 조사한 결과 최적 pH는 6, 최적 온도는 $37^{\circ}C$이었다. 우지를 기질로 액상 효소반응을 수행한 결과는 물사용량 80 wt/wt, 온도 $37^{\circ}C$, 효소사용량 200unit/g tallow 조건에서 93의 가수분해율을 얻을 수 있었다.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.115-120
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• 1997

Penicillium sp.-L4, a causative fungus of rot in citrus fruits, was isolated and its mode of hydrolytic enzyme production was investigated. Carboxymethylcellulase (CMCase), polygalacturonase(PGase), extra- & intra-cellular $\beta$-glucosidase and cellobiase were produced drastically by addition of substrates in minimal media. Production of the hydrolytic enzymes were induced efficiently by cellobiose and cellooligosaccharides which were the products of cellulose hydrolysis, but repressed by addition of mono-saccharide such as glucose, raffinose, galacturonic acid. The relative activity of p-nitrophenyl-$\beta$-D-glucopyranoside(PNPG) hydrolysis was higher than that of cellobiose hydrolysis in extracellular enzymes, and reverse is true in intracellular enzymes. Intact enzyme production of P. sp.-L4 on lemon peel lesion was sequential. $\beta$-Glucosidase and CMCase were produced first and followed by PGase. The enzyme productivities and pH in lesions were coincident with optimal pH of each enzyme activities.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2741-2746
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• 2013

The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.